Exhaust system for grinding wheels and the like



L. OFTEDAL Nov. 25, 1952 EXHAUST SYSTEM FOR GRINDING WHEELS AND THE LIKE Filed March 15, 1952 Patented Nov. 25, 1952 EXHAUST SYSTEM FOR GRINDING WHEELS AND THE LIKE Lars Oftedal, Oslo, Norway Application March 15, 1952, Serial No. 276,838 In Norway MarchZO, 1951 3 Claims. 1 The present invention relates to a suctionhood adapted to be employedin connection with grinding, polishing and like machines, for the purpose'of carrying away the dust or the like produced during the operation of such structures.

In devices of this class it appears that the grinding wheel entrains considerable air upon its rough sides causing a fan-like effect, setting up air currents resulting in a strong outward flow of air from the hood opening, especially at the upper part thereof, where particles of grit and metal leaving the wheel, are thrown outwardly beyond the hood by said outward flow.

The main object of the invention is to utilize the fan-like efiect of the wheel, creating a vacuum at both sides of the middle thereof, to counteract the said outward flow through the hood opening.

With this general object in view the invention consists in an exhaust system for a grinding wheel or the like, a hood enclosing the major portion of the wheel and having an opening in the upper forward portion thereof, a main exhaust duct communicating with the hood, outwardly directed enlargements in either side of said hood adjacent the middle of the wheel, radially extending grooves in the opposite wall portions at the upper front edge of said hood, said grooves communicating at the inner ends with the adjacent enlargement and at the outer ends with the open air.

In the drawing illustrating as an example an embodiment of the invention, Figure 1 is a rear elevation of an exhaust hood embodying the present invention; Figure 2 is a vertical cross section taken on the line IIII of Figure 1, Figure 3 is a plan view of the rear half of the hood in horizontal cross section and Figure 4 is a cross section similar to the upper portion of Figure 2 of a somewhat modified embodiment.

In the drawing l denotes the grinding wheel secured on a shaft 2 rotatably mounted in the bearing 3 of the grinding machine. The hood consists of two halves 4 and 5 which enclose the major portion, for example about three quarters of the circumference of the wheel, so that an opening is left in the upper forward portion of the hood as shown. At the bottom the halves form a main exhaust duct 5 for carrying away the dust, grit and metal particles created during the grinding operation. The halves 4 and 5, the division plane of which preferably coincides with the middle plane of the wheel enclose the wheel in such manner that between the sides thereof and the walls of the halves there is left only narrow slitsI, except at the middle of each halves where the walls have outwardly directed cuplike enlargements 4', 5', respectively, receiving the end of the shaft 2 and the means for securing the wheel I thereon.

The half 5 is secured to the bearing 3 of the grinding machine by means of screws 8. At the lower side the halves 4, 5 are interconnected by means of hinges 9 and at the upper side by means of a clamping bolt Ill.

At the upper front edge of the hood, where the wheel I runs out therefrom, each of the halves 4, 5 is provided with a vertically disposed groove or channel ll, having a cross-section which preferably increases toward the axis of the hood. Said channel or groove thus extends approximately radially and communicates at the inner end with the adjacent enlargement and at the outer end with the atmosphere.

Across the space between the halves at the upper ends of the channels II a tightening piece or gate I2 is arranged the sides of which project somewhat into said channels II and are guided therein so that the gate can be adjusted in the longitudinal direction of the channels in order to be placed in the correct position in relation to the diameter of the wheel. The lower part of the gate I2 has mainly the shape of an inverted U the legs of which lie close to the circumference of the wheel I and close the space between the halves 4, 5 intermediate of the channels so that said channels besides being communicating with the open air, also communicate with each other through the channel or port I3 formed by the said legs and the circumferential surface of the wheel I.

Each of the halves 4, 5 has mounted therein a curved partition 4", 5" respectively which cooperate to define conduit I4. The partitions are terminally spaced from the gate I2 as shown at I5 and extend down to the main duct 6.

In the operation of the device as above described the fan-like eifect of the wheel I during rotation thereof sets up air currents outwardly against and along the curved partition, as shown by arrows in Figure 1, said air currents being deflected by the gate I2 into the channel I4 and are exhausted through the duct 6.

This displacement of air by the rotating wheel creates in the enlargements at both sides of the Wheel I a vacuum efiecting a suction in the grooves Ii creating a downwardly flow of air therethrough which pick up the dust, grit and metal particles and carry them down through the grooves or channels II so that these do not continue outwardly beyond the hood. Owing to the channel or port 13 in the gate the suction in the grooves or channels II is equalized.

As will be understood the gate may have such a width that it extends to the bottom of each of the grooves II as shown at I2 in Figure 4. In this case the gate is provided with a bore I 6 connecting the channel I3 with the open air. The cross sectional area of said bore may be adjusted by means'of a slide valve H having a corresponding bore H3, or the like.

I claim:

1. In an exhaust system for a grinding wheel or the like, a hood enclosing the major portion of the wheel and having an opening in the upper forward portion thereof, a main exhaust duct communicating with the hood, outwardly directed enlargements in either side of said hood adjacent the middle of the wheel, radially extending grooves in the opposite wall portions at the upper front edge of said hood, said grooves communicating at the inner ends with the adjacent enlargement and at the outer ends with the open air, a gate closing the opening in the hood intermediate of the grooves and ar- 4 ranged adjustably in the longitudinal direction of said grooves, and a channel in said gate connecting the grooves at both sides of the wheel.

2. In an exhaust system as in claim 1 in which the gate extends to the bottom of each of said grooves, a bore connecting the channel in said gate with the open air and means for adjusting the cross sectional area of said bore.

3. In an exhaust system as in claim 1 in which the cross sectional area of said grooves increases towards the center of the hood.

LABS OFTEDAL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 956,762 Furrow May 3, 1910 1,217,996 Partridge Mar. 6, 1917 FOREIGN PATENTS Number Country Date 563,537 Germany Sept. 25, 1931 

